Bad Tests Die Slowly: The Myelin Basic Protein Example.

Background: Our national reference laboratory sought to improve stewardship for multiple sclerosis (MS) testing, which included orders for myelin basic protein (MBP) and oligoclonal bands (OCB). From 2011 to 2012, we performed 2 interventions for MS testing: one gentle-strength intervention of a publication designed to educate others about the lack of utility for MBP results and a second medium-strength intervention that included removal of MBP from the panel of MS tests. The ordering trends and practice variation were examined for OCB and MBP to retrospectively observe the effect of the interventions. Methods: Data from clients within academic and community hospitals were examined (n = 1710 clients). Ordering patterns for OCB and MBP were investigated from 2008 to 2018 by calculating the %OCB: %OCB = (OCB)/(OCB + MBP). Practice variation was examined by comparing the distribution of clients with different %OCB statistics before and after the interventions in 5-year blocks (2008-2012 vs 2014-2018). Results: From 2000 to 2011, the %OCB was approximately 50%, but gradually increased to 67% in 2018. For practice variation, analysis of the distribution of clients by %OCB also demonstrated a shift toward clients favoring OCB alone vs OCB + MBP for MS testing for the later time period of 2014-2018. Conclusion: Our 2 interventions had a measurable, beneficial effect on ordering trends for MS testing over a 10-year period at a single reference laboratory. However, given that MBP has questionable clinical utility, stronger interventions are likely needed to bring about larger changes in ordering behavior.